Add @garymoon to MAINTAINERS (#24752)

Hi all.

I would like to apply to be a maintainer please. I have [four accepted
PRs](https://github.com/go-gitea/gitea/pulls?q=is%3Apr+author%3Agarymoon)
(such as they are), sign my commits, and have MFA enabled everywhere. My
hope is to continue with code contributions where I can (I'm not a
developer, just a wannabe), take some work off kdumont's hands, and
contribute on the infrastructure side where there is room 💚 🍵

Thank you!

Author: garymoon

MAINTAINERS

@@ -50,3 +50,4 @@ Eddie Yang <[email protected]> (@yp05327)
 Dong Ge <[email protected]> (@sillyguodong)
 Xinyi Gong <[email protected]> (@HesterG)
 wxiaoguang <[email protected]> (@wxiaoguang)
+Gary Moon <[email protected]> (@garymoon)